Lifting-jack.



No. 635,105. Patented Oct. I7, |899. T. MAxoN.

LIFTING JACK.

(Application led June 8, 1899.)

4. @zwi/t V N A d I 1 W/a,

L* l l l i Patented Uct. I7. |899.- T. MAXON.l

LlFTING JACK.

(Application led June B, 1899.)

2 Sheets-Sheet 2,

(No Model.)

J NiTnn4 STATESV PATENT LIF'TING-JACK.

SPECIFICATION forming part of Letters Patent No. 635,105, dated October17, 1899.

Application filed June 8, 1899. Serial No. 719,827. (No model.)

To all whom, t may concern:

Be it known that I, TgHoMAs MAXON, a citizen of the United States,residing at Dayton, in the county of Montgomery, State of Ohio, haveinvented certain new and useful I1n provements in LiftingeJacks; and Ido hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilledinthe art to which it ap pertains to make and use the same, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention is designed to provide a strong and durable lifting-jackof that class wherein the load is adapted'to be let down, when occasionmay require, gradually by a stepby-step movement, as more fullyhereinafter set forth.

Referring to the drawings, Figure l represents a vertical sectionalView, a part only of the lifting-pawl being shown in section at itslower end; Fig. 2, a side elevation withvone of the anges surroundingthe fulcruin-slots in section; Fig. 3, a horizontal section on the line3 3 of Fig. l; Fig. 4, a detail perspective of the cam device foroperating the retainingpawl when gradually lowering the load; Figs. 5and 6, vertical sectional views with the lower portions of the standardand lifting-bar broken away, these views showing the de vices in thevarious positions assumed in let-1 ting down the load gradually step bystep; Fig. 7, a section on the line 7 7 ot' Fig. l, and Fig. 8 a detailof the cam device and releasing-pawl in one of the positions they assumein letting down the load gradually.

Referring to the drawings by letters, a designates the hollow standard,in which works the lifting-bar c, which is provided with the usualratchet-teeth on its rear edge and is cast with a lifting foot or toe dat its lower end. The lifting-bar is cored out throughout its length, soas to equalize the iron at all points, and fitted nicelyin said verticalpassage is a steel bolt e, which is provided with a foot-piece f at itslower end which extends forward to the outer end of the foot d and liesin a channel or recess formed in the under side thereof, said bolt beingdrawn taut by a suitable nut at its upper end. This bolt Vfastened tothe inner face of the pawl.

greatly strengthens the bar, as well as the lifting-foot, this latterfeature being important.

Journaled in the casing or standard, near the upper end thereof, upon apin b is a horizontal roller g, against which bears the front edge ofthe lifting-bar, whereby friction is avoided at that point. Aretaining-pawl h is mounted in a recess in the upper end of the casingand is kept normally pressed against the lifting-bar by a spring t,which su rrounds the operating-pin j, which latter extends out to anopening in the rear wall of4 the casing, whereby the' pawl may bereleased from the lifting-bar b y hand or by other means hereinafterdescribed.

At a point a suitable distance below the retaining-pawl the respectiveparts of the casing are provided with rearward-extending integralbrackets 7c, which are separated from each other a sufficient distanceto receive the end of the operating-lever l, the extreme inner end ofthe operating-lever beyond the fulcrum-pin m being bent inward andupward and being bifurcated for thereception of the pivoted lifting-pawln, which is provided at its upper end, above its pivotal connection withthe lever, with a series of teeth o, these teeth being made ofcase-hardened steel and The pawl works vertically in an opening in therear wall of the casing and is provided with a depending tailpiece p,which is provided with vertical flanges q on its side faces for thepurpose of lightening and strengthening it. The tailportion of the pawlis prevented from swinging outward by means of a casehardened-steelrollerr, j ournaled upon a hori zontal pin or bolt carried by thestandard, and one of the inner walls of the casing is provided with alug s, which assists in vertically guiding the pawl, preventing itswinging inward against the ratchet-teeth on the lifting-bar, said luglying between the flanges q, one of the flanges being cut away at t topermit the pawl to be inserted in its place between the walls of thecasing. The upper end of the pawl, when the pawl is at the upper limitof its stroke, abuts against the stop u/which isa part of the casing.The fulcrum-pin m is made of steel and is rigidly fixed in the lever,its projecting ends carry:

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ing case-hardened-steel rollers o, which work in U shapedcase-hardened-steel bushings w, fitted in flanged slots formed in thebrackets k, said slots inclining upward and rearward. The slots arecovered by means of removable plates y, fastened to the flanges a aroundthe slots.

The operation of lifting is obvious. Upon each downward stroke of thelever the lifting-pawl engages the lifting-bar and raises the same, theretaining-pawl being forced outward by a cam action of the lifting-teethon the bar and automatically springing into engagement again when theupward movement of the lifting-bar ceases. To drop the bar, itis simplynecessary to withdraw the retaining-pawl by hand or otherwise, thelifting-pawl being disengaged from the liftingbar by drawing theoperating-lever outward until rollers fu enterthe outer or upperextremity of the slots x, the tail portion of the pawl bearing againstroller o", this roller serving as a pivot, as shown most clearly in Fig.5. The slots x are slightly enlarged or turned slightly backward attheir upper extremities to facilitate this movement, the rollers passinginto this enlarged or angular extremity of the slots, as shown in saidFig. 5. In the operation of lifting the rollers do not move into thebent or enlarged portions ofthe slots,

but simply roll back and forth upon thev bushings.

It will be observed that the rollers not only serve to reduce thefriction of the pawl in its vertical movements, but also serve as apivot whenthe upper part of the pawl which carries the lifting-teeth isswung outward out of engagement with the lifting-bar, and it will alsobe observed that the bushings w take up all the wear in the slots andmay be renewed when worn. In fact, it will observed that all the partswhich are likely to become worn by the severe strain'and friction thatjacks of this sort are subjected to are removable and renewable.

The devices for letting down the load step by step are very simple,consisting of a camwedge d', embracing the pin j and adapted when drawndown to have its cam edges Z9 bear against the projecting portions of atransverse pin c', carried by said pin j, and thereby withdraw theretaining-pawl from the lifting-bar and hold it out, the inclined camedges b' terminating at their upper ends in straight portions d in orderto hold the pawl positively out of engagement. Between the walls of thelower end of the cam-wedge is pivotally swung upon a pin c' a swinginglink j", which is adapted to swing loosely inward and outward and has alimited vertical movement by reason of the slot g where pin el passesthrough it. This link` is provided at its lower end with a longitudinalslot 71.', this slot having the entrance-opening t, whereby the link maybe engaged with and disengaged from horizontal pinj, xed rigidly in apair of upwardly-extending ears 7c upon the lever Z. When theletting-down devices are not in use, the cam rests normally on pin c',and the link f swings loosely from the cam, its lower end lying betweenthe brackets 71;.

To let down the load step by step, it is simply necessary to draw downor depress the 0perating-lever until the cam disengages theretaining-pawl, care being taken to first see that the lifting-pawl israised to the limit of its upward stroke, the pawl in Fig. 5 being shownin the act of being lifted preparatory to withdrawing theretaining-pawl. When the retaining-pawl is out, the weight will bethrown upon the lifting-pawl and through it to the operating-lever. Theoperator then allows the lever to, be raised by the downward pressure ofthe load. Then when the load has descended a distance of one or moreteeth, according to the size of the teeth and the adjustment of theparts, the lost motion caused by the slots in the linkf will have beentaken up and the link will push up the cam and disengage the retainingpawl, permitting the same to spring into engagement with thelifting-bar. To repeat, the operator draws out the operating-lever farenough to disengage the lifting-pawl from the lifting-bar, as shown inFig. 5, then depresses the lever, allowing it to swing inward, so thatthe lifting-pawl will again engage the lifting-bar just below stop u, asshown in Fig. 5. Then by continuing to depress the lever theretaining-pawl will be drawn out and held out ofengagement until thelifting-bar is lowered the desired distance, whereupon it is againautomatically tripped by the continued upward movement of the lever, theweightbeingagain thrown upon the operating-lever through the medium ofthe lifting-pawl.

I claiml. In a lifting-jack, the combination of a standard,alifting-hama retaining-pawl, a lifting-pawl provided with teeth at itsupper end, said pawl being provided with a depending tail portion, abearing part, as a roller, carried by the standard and adapted toreceive the outward thrust of the tail portion, and an operating-leverpivotally supported on the standard and pivotally connected to thelifting-pawl near its upper end and adapted to swing inward and outwardas it is vibrated vertically, whereby when the toothed upper portion ofthe pawl is disengaged from the lifting-barbyswingingoutward the upperend of the pawl the lower end of the pawl will work on said bearing partas a pivot, as and for the purposes set forth.

2. The combination of a standard, a liftingbar working therein, aretaining-pawl, a lifting-pawl provided with a depending tail part andvertical separated side flanges q, a roller r and the lug s, arranged asdescribed, for guiding the pawl vertically and preventing it swingingoutward from the lifting-bar at its lower end and an operating-leverpivotally supported on the standard and pivoted to said lifting-pawl andbeing capable of moving out- IOS) IIO

ward and backward at its fulcrum-point, whereby upon disengaging theteeth of the lifting-pawl the tail part thereof will work on the rolleras a pivot.

3. The combination of a standard or casing, a lifting-bar workingtherein, said casing having its rear walls extended Vto form'brackets,these brackets being slotted upward and backward, the extreme upper endsof said slots being extended backward slightly, a lever carrying afulcrum -pin provided with rollers working in said slots, a lifting-pawlcarried by said lever and adapted to have its teeth disengaged from thelifting-bar by the fulcrum-rollers passinginto the bent upper ends v ofsaid slots.

.ing-pawl will be released automatically and rengage the lifting-bar,thereby enabling the lifting-bar to be lowered step by step by avertical vibration of the lever.

5. The combination ot' a standard, a liftingbar, a retaining-'pawlsupported on the standard, a lever journaled on the standard below theretaining-pawl, a lifting-pawl carried by the lever, a device carried bythe standard and adapted when drawn down upon'to automatically Withdrawand temporarily hold out of engagement the retaining-pawl, and adetachable connection between said device and the lever this connectionhaving lost motion between the lever and said device whereby thedepression of the lever will automatically withdraw the retaining-pawland hold it out of engagement and the upward movement ot the lever willautomatically release the retaining-pawl at a predetermined point,forthe purpose set forth.

6.. The combination of a standard, a lifting bar, a lever journaled onthe standard, the

fnlcrum of said lever being adapted to move outward from said standard,a lifting-pawl carried by the lever and adapted to be disengaged fromthe lifting-bar when the lever is moved outward, a retaining-pawlsupported on the standard, a spring normally holding draw theretaining-pawl and when the lever is raised it will automaticallyrelease the retaining-pawl at a predetermined point, for the purpose setforth.

y 7. The combination ol a standard, alifting- -bar, a retaining-pawl,supported on the standard, a lever journaled on the standard, andcarrying a lifting-pawl, a sliding cam adapted when drawn down torelease the retainingpawl and hold it temporarily ont of engagement, anda link connecting said cam to the lever, said link having longitudinallost motion, for the purpose set forth.

8. The combination of a standard, a liftingbar, a retaining-pawl, a camdevice for withdrawing the same, a lever carrying the lifting-pawl andjournaled upon the standard, and a device connecting the lever to thecam whereby when the lever is depressed the cam will withdraw theretaining-pawl and when raised will release the retaining-pawl at apredetermined point in its upward movement.`

9. The combination of a standard, a liftingbar, a lever carrying alifting-pawl and journaled upon the standard so as to move inward andoutward as it is vertically vibrated, a

spring-actuated retaining-pawl, a cam device taining-pawl and hold itout of engagement,

and a link connecting said cam to the lever, said link being detachableand having a longitudin al motion independent of the lever and cam.

In testimony'whereof l hereunto afiix my signature, in the presence oftwo witnesses, this 5th day of June, 1899.

THOMAS MAXON.

i Witnesses:

Trios. A. WIATT, H. J. WILooXEN. i

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